Linear and helical chains in hydrothermally synthesized coordination polymers [Co(bpdc)(H2O)2] and [Ni(bpdc)(H2O)3]•H2O involving in situ ligand synthesis

Hydrothermal treatment of M(MeCO2)(2) (M = Co or Ni) and 1,10-phenanthroline-5,6-dione (pdon) resulted in two chainlike coordination polymers [Co(bpdc)(H2O)(2)] and [Ni(bpdc)(H2O)(3)].H2O. X-ray single-crystal structural analysis revealed that the organic reagent pdon was transformed in situ into 2,2'-bipyridine-3,3'-dicarboxylate (bpdc). The different coordination modes concomitant with the difference of the dihedral angles between two bpdc pyridine rings results in simple linear chains and helical chains in 1 and 2, respectively. The one-dimensional coordination chains of 1 and 2 are further extended into two-dimensional supramolecular arrays by hydrogen-bond interactions. A possible mechanism for the new hydrolysis reaction with the formation of bpdc under hydrothermal conditions was also discussed. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.